Continuous tumbling mill



Aug. 7, 1951 D. c. TURNBULL 2,553,084

CONTINUOUS TUMBLING MILL Filed May l, 1948 5 Sheets-Sheet l IN V EN TOR. DAA V/o C. TURA/BULL ,4 TTR/VEKS' 55%, MMM

Aug. 7, 1951 D. c. TURNBULL 2,563,084

CONTINUOUS TUMBLING MILL Filed May 1,` 1948 5 sheets-sheet 2 CHA RG: Hop/DER OOOOO oooooooo OGPOOOOO oooooooe ooooooco D/SC//RGE HOPFER INVENTOR.

DA v/D C. TURA/BULL m, m 7 M TTORN E YS Aug. 7, 1951 D. c. TURNBULL CONTINUOUS TUMBLING MILL 5 SheetS-Sheet 5 Filed May l, 1948 INVEVTOR. DA v/D C, TURA/BULL m, hfwm ATTRNEKS.

Aug. 7, 1951 D. c. TURNBULL 2,553,084

CONTINUOUS TUMBLING MILL Filed May 1, 1948 5 sheets-sheet 5 INVENTOR. DAV/0 C. TURA/BULL A BY M my /WL Patented Aug. 7, 1951 `CONTINUOUS TUMBLING MILL 'David C. Turnbull, Mishawaka, Ind., assigner to American Wheelabrator & Equipment Corporation, Mishawaka, Ind., a corporation of Neliraska Application .May 1, 1948 Serial No. 24,510

9'Claims. 1

The invention relates to treating metal or other articles, and more Aparticularly to a mill for cleaning, polishing, hardening, or otherwise treating, such objects as metal castings, forgings and the like.

According to a preferred embodiment of the invention, the mill comprises an endless tumbling conveyor supported by upper and lower shafts and forming upper and lower plies. The upper ply forms an outwardly concave pocket 'which holds the `workpiec'es to be treated. The conveyor moves in a direction from its lower Ashaft toward lits upper shaft; this movement carries the workpiecfes with it to some point 'from which the workpieces fall back, describing a generally 'tumbling action. A special tie chain rides on sprockets on the upper and lower conveyor shafts to maintain proper relationship between positions of the upper and lower plies.

The tumbling conveyor is -located within a cabinet at the Ytop of 'which is located one or more airless blast wheels which project through into the cabinet roof and rdirect a blast of treating particles on vthe workpieces 'being tumbled.

Extending across the one side of .the workhold'ing pocket of the tumbling conveyor is one ply of `an endless feed conveyor lwhich maybe in the `form of a flexible belt. As the workpieces are tumbled, they'fall back against this ply'whic'h gradually moves the workpieces :from the feeding end of the 'milljto the vdischarge end of the mill. VThe :feed conveyor may be 'laterally supported by a'verti'cal'backing plate.

The feed end of the rmill is provided with a charge hopper vor feed chute into which the articles to be treated are fed. The discharge end of Athe Vmill is provided with a discharge chute into Vwhich the treated articles 'are automatically fed and from which they are "removed from the mill. The feed conveyor passes through part of .the charging 'and'discharging chutes which are disposed adjaccnt'end extensions on the cabinet. :These extensions house drums 4for supporting the feed conveyor belt.

The bottom lof the cabinet has sloping Vwalls forming a receiving hopper which receives the spent blast material. This hopper guides this material to a bucket elevator located alongside the cabinet. The bucket elevator may carry the blast material to 'suitable cleaning land 'screening devices located above the `mill whence 'the material is re-circulatedback to the blast wheel.

The tumbling conveyor, feed conveyorand blast wheel are independently -drivenby separate velectric motors. `Speed changing devices are incorporated in the 'drives to the tumbling conveyor and to Athe feed conveyor so that the speed of each conveyor may be independently adjusted to give best results for each Vparticular type of work being treated.

Features of the present invention include the use of the independently controlled feed 'conveyor Iand its relationship 'to the tumbling conveyor and other 'parts of the mill; the tie chain for retaining fixed relationship between upper and lower 'tumbling conveyor plies; the lparticular constructions of the tumbling and feeding conveyors.

'The invention also consists in certain vnew and original features and combinations 'hereinafter set forth and claimed.

Although the novel features which are believed to be 'characteristic -of this invention will be particularly pointed out in the claims appended hereto, `the invention itself, as to its objects and advantages, and the manner in which it may be carried out, may be betterunderstood by referring to `the following description taken in connection with the Aaccompanying drawings forming va part hereof, in which:

Fig. A1 is aside elevation with parts broken away to show the tumbling conveyor 4and vthe feed conveyor;

Fig. 2 is va 'front section taken onthe lin-e 2-'2 of Fig. l;

Fig. 3 'is a plan view with vcertain parts -in section;

Fig. 4 is a section taken 'on the line 4-4 of Fig. `2 and illustrating the tumbling conveyor and the discharge chute;

Fig. 5 is a detail of the tumbler conveyor flights 4and 'manner of mounting on conveyor chains;

Fig. 6 is a section on the line :l-B of Fig. `5;

Fig. '7 lis a detail of a modied form 'of tumbler conveyor iii'ghi, construction, this YView Vbeing specially prepared `to illustrate the Acapability of 'the conveyor Ato'fiex vin either direction;

Fig. '8 is a section on the line '8-8 :of Fig. 7';

Fig. 9 .is a lperspective of a modified 4form of feed conveyor;

Fig. l0 is a `fragmentary side velevation yof Ia modified form of mill using a rubber 'tumbling conveyor;

Fig. i1 is a longitudinal fragmentary section taken through the sprocket tooth holes of the -conveyor shown in'Fig. '10; and

Fig. l2 is a detail plan view 'of 'one of Athe sprocket tooth holes of the conveyor shown n Eig. 10.

in the following description 1and lin the claims, various details will be identified by specific names v.bottom of the bucket elevator housing I9.

blasting chamber has end walls 52 provided .ably riveted to a ight 3|.

3 for convenience, but they are intended to be as generic in their application as the art will permit.

Like reference characters denote like parts in the several figures of the drawings.

In the drawings accompanying and forming part of this specification, certain specific disclosure of the invention is made for purposes of eX- planation,.but it will be understood that the details may be modied in various respects without departure from the broad aspect of the invention.

Referring now to the drawings, and more particularly to Figs. l, 2 and 3, the mill comprises, in general, a cabinet, indicated generally by II'I, having a charge hopper or feed chute Il at one end of the cabinet, and a delivery or discharge chute I2 at the other end. Inside the .cabinet is a tumbler conveyor I3 and a feed conveyor I4. The tumbler conveyor I3 moves in the direction of the arrows A of Fig. 1, causing the workpieces to tumble in somewhat the manner indicated by the arrows B; at the same time, the workpieces are slowly" moved from feed chute to delivery chute by thev feed conveyor I4 moving in the direction of the arrow C in Fig. 3.

While the workpieces are being tumbled within the cabinet, they are subjected to a blast of particles from airless blast wheel I5. The spent blast particles are collected in receiving hopper I5 vwhence they are delivered to bucket elevator. I.

Elevator Il delivers the blast material to overhead hoppers for cleaning, or other treatment, Awell known in the art, from which the blast ma- .terial is re-circulated to supply chute It back to the blast wheel I5.

A more detailed description follows:

Th cabinet Ill is made up of the usual steel framework with steel panels to form an interior ,blasting chamber'in which the blasting occurs.

rThe cabinet has atop wall 2|; a front wall 22 with door 23; it hasa back wall 24; it has a bottom hopper i6 Whose bottom walls slope from end ..to`end, as shown in Fig. 2, and from front to back,

as shown in Fig. l, to deliver spent blast to the to house the feed conveyor pulleys 39.

The tumbler conveyor I3, Fig. 1, is mounted upon two main'horizontal shafts 2l and 28 suitably journaled in the cabinet walls. These shafts support sprockets 29 which, in turn, support conveyor chains 35, one on either side. Extending .between and beyond the conveyor chains 3E) are the slat-like flights 3l (see also Figs. 5 and 6).

`AThese flights, together-with the chains, form, in

effect, a wide, traveling, endless belt or conveyor.

The tumbler conveyor I3 is constructed as follows. The chains 30 are made up of a plurality of links 33 connected by pins 32. The pins support rollers 35 located between the links. On eachpin 32 is swiveled a U-shaped lug 34 suit- It will be noted that 'the successive flights 3| are mounted in overlapping relation and have longitudinally extending ribs 25 and flattened ends 26. The flights also have a plurality of holes to promote sifting through of the spent abrasive.

1t will be noted, particularly from Figs. 1 and 4, that the endless tumbling conveyor I3, as mounted on its two supporting shafts, forms an upper ply and a lower ply. The upper ply forms y The Y 4 a concave work-holding pocket and is constrained to move in a desired, approximately arcuate, path by guides 35 and 43 mounted on the end walls of the casing. The lower guides 33 are mounted directly under the rollers 35 so the rollers may roll on them and thus support the weight of the workpieces. The upper guide 43 may be locatedfdirectly, above the lower guides 33. The upper guides 43 are located behind the backing plate 40 and are thus protected from the blast.

-It will be seen that the tumbling conveyor I3 moves in theV direction of the arrow A in Fig. 1 and that the flightsV 3| are in overlapping relation as they pass through the work-holding pocket. As the upper ply of the tumbler conveyor passes over the sprockets on the upper supporting shaft 2l, the flightsi may swing outwardly, as indicated in Fig. 1. As the lower ply approaches the lower shaft 28 the nights swing back into overlapping relation.

The feed conveyor |4 comprises a at belt which may be made of some rubber-like, flexible material suitably reinforced by woven wire, etc. |This belt has its plies in a vertical plane, one ply passing through the posterior side of the work-holding pocket where it is supported by backing plate 4U. The other ply is located near the front wall 22 .of the cabinet.

The feed conveyor I4 passes through the end walls 5|, 52 of the cabinet and around supporting drums 39 mounted in the cabinet extensions 53, 59. The drums 39 have a lower radial flange to prevent the belt from slipping off.Y The drums 33 are mounted upon vertical shafts 31 and 38 suitably journaled in the frame of the cabinet and protected .from the blast.

The backing plate 40 is located where the feed conveyor I4 passes through the tumbling chamber. This backing plate extends throughout the length of the tumbling pocket and from end wall to end wall. The lower portion of plate 4I) laterally slidably supports the conveyor I4 and the upper portion is inclined somewhat to protect the tumbling conveyor I3 from the abrasive blast.

The bottom wall of the feed chute has an apron or extension 62 disposed over the projecting flights 3l of the tumbling conveyor, as shown in Fig. 2. The flights 3| of the tumbling ccnvveyor extend over an inwardly deected end wall or apron 33 at the discharge opening. The feed conveyor I4 forms part of the'side wall of the feed chute II and of the discharge chute I2 (see Fig. 3).

The delivery chute I 2 has holes 34 in the bottom communicating with the bottom hopper I6 to discharge any entrapped blast particles which may be carried out with the workpieces. The delivery chute may have an open top as indicated by 'Ill in Fig. 4.

Both the inlet and outlet openings in end walls 5I and 52 are in substantial register with the work-holding pocket as defined by the feed belt I4 and by the vertical rise of the tumbling conveyor which limits the tumbling travel of the work.

Vcommerciially as4 the Wheelabrator, manufacasados@ tured by American Wheelabrator 8fv Equipment Corporation, of Mishawaka, Indiana.

When blast material is. fed by feed spout 42 to. the center o-f the wheel I5, the Wheel delivers a blast whose pattern is indicated somewhat by the lines 4I= in Fig; 2. This blast impinges upon the work being tumbled. in the tumbling pocket of the tumbling conveyor, thoroughly treating the workpieces` on all surfaces. This blastv may be an abrasive blast for cleaning castings and the.` like; or it may be ay peening blast for condi-V tion'ing.' the surface of the workpiecesi; or it may be2- a honing or finishing blast of. a liquid slurry made up of polishing or honing particles carried by suitable liquid. vehicle; If desired, a plurality of. blast wheels,l instead of the. single wheel shown, may be used.

It. will. be noted thatv the blast pattern of the single wheel illustrated is elongate in. the direc tion of. feed movement' off the workpieces through the machine, that is, lengthwise ofthe trough. or pocket; formed by the tumbling conveyor. 'l'.he blast pattern is. comparatively narrow in the direction of tumbling movement so as. to` avoid undue wear on backing plate 4Q and feed. con veyor I4. The work being tumbled receives the full effect of the blast.

The blast particlel circulation is as follows. Blast material is supplied to the center of. the

blast wheel l5 by the feed spout 42', as is well known by'those skilled. in the art. The blast ma-` terial,` after blasting the workpieces, lters throughand around, the workpieces and through the tumbling conveyor and is finally collected in the collecting hopper Iii. The spent material then flowsi by gravity to the: bottom of bucket elevator; Il which` raises the spent material to a point', above the cabinet where thel abrasive may be.y cleaned or otherwiseV treated by standard appliances. The blast' material is then returned to the supply hopper t8, whence it passes to. feed spout 4:2 to complete the cycle.

The'turnbling` conveyor, the feed conveyor, and blast wheel Aare all separatelyl driven by sepa-- rate electric motors'.

The tumbling conveyor I3 is driven by motor 45` mounted. at. the topY oi. thev cabinet. Motor :i5: drives gear reducer,` 46 through beltv 4l. Gear reducerllt drives topsupporting shaft. 2l' by chain 48.. Tumbling conveyor supporting shafts 2l. and 218.A are tiedl togetherby a tie. chain. 49' riding on; suitable. sprockets mounted on the ends. of these shafts. This tie chain. 49 drives the lower sup.n porting shaftv 2B. at the same speed as the upper shaft 2.7r to keep the lengths of` thek upper and lower. plies of the tumbling conveyor I3 in iixed relationshipr The feed conveyor I4 is driven by motor 53 mounted upon top of the cabinet extension. Motor 5i)A drives; belt 54 which drives speed'reducer 55E; speed reducer 55 drives drum shaft 31 through chain 5.61

The'blastwheel' I5 is driven by motor SE. mount# ed: on top ofi thev cabinet. 'Motor 60 drives blast wheel I5 through multiple belts 6i.

The speed reduction from the several drive motors 45 and 53 are independently adjustable by adijustingfwheelsill and 51 so that' thespeeds of the tumbling conveyor I3 andi-'of the feed conveyor I4 may be independently adjusted for each particular class-of work. The speed-adjusting wheels- 55 and 5ft-adjust the positionsiof motors 45t and 53i and` thereby the'v eifective diameters ofthe motorpulleys as is well known with this type ofY variablespeeddfriVe.r -I

T'ouse the mill,- the conveyorV motors and the blast wheel motor are started and blast cycle started.v The workpieces are: fed into the feed hopper II by suitable conveyor means (not shown)-. mediately/ contact the feed conveyor i4 moving direction of arrow C Fig'. this: carries the Work intorthe mill, through thev mill and out into the discharge chute I2 where asuitable. conveyor (not shown) may be. provided for receiving the treated pieces.

As the workpieces enter upon the tumbling conveyor' |531, they are carried` upwardly to a certain distance toward the vertical section of the conveyor, after' which they fallback against the feed conveyor describing a tumbling action somewhat as indicated by the arrows B in Fig. 1. This tumbling action exposes all surfaces of the work tol the blast. At the same time contact ofl the workY with the feed conveyor I4 slowly carries the work through the blasting chamber.

Both tumbling speed and feeding speed can. be nicely and independently controlled bythe operator tosuit the kind of work being treated. These speeds may be determined by trial or fromv pre-v vious experience. Fragile work may require slower tumbling to avoid breakage. Dirty castings re.- quiri-ng more blastingy will generally require slower feeding movement through the machine than comparatively clean castings.

The support of the tumbling conveyor I3 on two shafts 2.1 and 28' with the tying chain 49 maintains the positions of the conveyor loops or plies and reduces the drag of the conveyor chains on the. supporting tracks 35i and guide bars 43. These tracks and bars also` limit sideswayA and hold the upper ply in the arcuate or other desired form.

The door 23 in the front oi the cabinet permits access to the interior of the mill for observation, to remove work. that may jam, and for replacement of parts. The entrance and exit openings to the cabinet with respect to the blast pattern and in relation to the feed and discharge chutes facilitates sealing inof the flying blast particles.

l gives nice adjustment to the speed of tumbling and to the speed of conveying the workpieces through the machine'. The action of the present machine handles, equally well, comparatively round workpieces which tendV to pass more easily through the blast zone and'elongate or angular workpieces which do not move so easily. The feed conveyor extending into thefee'd and discharge chutes-reduces jamming that may otherwise ocour at the feeding or discharge points.

Referring now to Figs. l and 8, a modified form: of tumbling conveyor I3 may be used instead of conveyor I3. Here the two chains 39 may be madeup'of U-shapeol links Sb connected by pins 6T. Located between the links on the pins are rollers 69. I'n thisA case vthe links GS have an inclined cross piece to which the flights E5 are rigidly connected by bolts 68; It will be noted that the flights are similar to the flights 3| of Figs. 1 to 6".

It will benoted that the flights 65 are rigidly mounted on their particular links 66 and are not pivoted thereto asin Figs. 1 to 6; The flight construction is such that the flights have normal overlapping relation when the conveyor I3" is concave upwardly, which is its shape Ywhen support- The workpieces in. feed hopper II im.

aceaosc ing the workpieces. Such relationship is illustrated -by the links Y and Z in Fig. 7, which figure was specially prepared to illustrate the capability of the conveyor i3' to flex in opposite directions. The relationship between links X and Y in Fig. 7 illustrates the position these links will take when the tumbling conveyor I 3 takes an outwardly convex position, as when passing around the supporting sprockets.

Referring to Fig. 9, the modified feed conveyor I4 here is provided with a plurality of cleats or angle irons 'I2 suitably riveted to the flexible wirereinforced band, to Yassist in carrying the workpieces through the blasting zone. This may be used in place of feed conveyor' I4 of Figs. 1 to 6.

Referring now to Figs. 10 to 12 a mill is shown with afurther modified form of tumbler conveyor I3". The parts are otherwise generally similar to corresponding parts in Figs. 1 to 6 so will not be again described; similar parts are denoted by the same reference characters with double primes added.

The conveyor I3" is made up of a flexible band of rubber or other tough flexible material suitably reinforced by steel Wire. The conveyor has a series of sprocket openings along its length, which openings are lined by metal liners 'I5 which engage the teeth of sprocket 29". These metal liners 'l5 may ride upon the curved upper and lower supports 43, 36" which compel the tumbling conveyor to take the desired shape and which also support the upper ply where the work is being tumbled.

While certain novel features of the invention have been disclosed herein, and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

l. A continuous mill for treating workpieces, said mill comprising a tumbling conveyor, means causing said conveyor to move the workpieces from a lower position to an upper position carrying the workpieces along and then causing them to tumble back, a separate movable feed conveyor extending across the direction of tumbling movement of said workpieces, means for arranging said feed conveyor to provide a moving back stop against which said workpieces fall as they tumble back, said feed conveyor serving to advance said workpieces generally across the direction of tumbling movement.

2. In a mill, a tumbling conveyor comprising upper and lower shafts spaced both horizontally and vertically, wheels on said shafts, an endless carrying element riding said wheels, said carrying element forming upper and lower pliesthe upper ply forming an upwardly concave pocket to support the workpieces, a feed conveyor extending across said tumbling conveyor and through said pocket at the posterior side thereof, whereby the movement of said tumbling conveyor carries'the workpieces away from said feed conveyor and causes them to tumble back against said feed conveyor. f

3. In a mill, a cabinet having upper and lower shafts spaced horizontally and vertically, an endless tumbling conveyor supported by said shafts and forming upper and lower plies, means for causing the upper ply to form an upwardly concave pocket to tumble the workpieces, an endless feed conveyor having a feed ply disposed in said pocket, said ycabinet having feed and discharge openings in its end walls throughrwhich said feed ply extends, said feed ply being so positioned in said pocket that it carries said workpieces from said feed opening to said discharge opening and subjects them to the action of said tumbling conveyor.

4. In a mill, a cabinet having upper and lower shafts spaced horizontally and vertically, an endless tumbling conveyor supported by said shafts and forming upper and lower plies, means for causing the upper ply to form an upwardly concave pocket to tumble the workpieces, a feed conveyor disposed in Said pocket and extending across the tumbling conveyor, said cabinet having end Walls through which said feed conveyor extends, said end walls having a feed opening and a discharge opening, a feed chute connecting said feed opening, a discharge chute connected to said discharge opening, said feed conveyor extending into said feed and discharge chutes so as to carry workpieces into said pocket7 through the mill and out of the mill.

5. In a mill, a cabinet having upper and lower shafts spaced horizontally and vertically, an endless tumbling conveyor supported by said shafts and forming upper and lower plies, means for causing the upper ply to form an upwardly concave pocket to tumble the workpieces, a feed conveyor comprising an endless band having one ply generally vertically disposed in said pocket, said cabinet having end walls through which said feed Conveyor ply extends, extension housings at the ends of said cabinet, drums journaled in said housings supporting said feed conveyor, said end walls having a feed opening and a discharge opening, a feed chute connecting said feed opening, a discharge chute connected to said discharge opening, and a backing plate extending from feed opening to discharge opening against which the feed conveyor rides to support the latter against the pressure exerted by the workpieces.

6. In a continuous mill, a cabinet having upper and lower shafts spaced horizontally and vertically, an endless tumbling conveyor supported by said shafts and forming upper and lower plies, means for causing the upper ply to form an upwardly concave pocket to tumble the workpieces, a feed conveyor comprising an endless band having one ply generally vertically disposed at the posterior side of said pocket and the other ply on the opposite side of said lower shaft, said cabinet having end walls through which the plies of said feed conveyor extend, extension housings at the ends of said cabinet, drums journaled in said housings supporting said feed conveyor band, said end walls having a feed opening and a discharge opening, a feed chute connecting said feed opening, a discharge chute connected to said discharge opening, said feed conveyor extending into said feed and discharge chutes so as to carry workpieces into the mill, through the mill, and out of the mill, a backing plate extending from feed opening to discharge opening against which said feed conveyor rides to support the latter against the pressure exerted by the workpieces, and an airless blast wheel projecting through the top wall of the cabinet and directing a blast on the workpieces being tumbled.

7. A continuous mill for treating workpieces, said mill comprising a tumbling element for tumbling the workpieces, a feed conveyor extending across the direction of movement of the workpieces for feeding the workpieces as they are being tumbled, said tumbling element and conveyor being so related that said workpieces are contacted by both the tumbling element and the 9 conveyor, and treating devices for treating the workpieces as they are being tumbled and fed through the mill.

8. The mill according to claim 7 in which means are provided for adjusting the speed of the feed conveyor independently of the speed of the tumbling element.

9. A continuous mili for treating workpieces, said mill having a tumbling zone and comprising a tumbling conveyor for tumbling the workpieces in the tumbling Zone, a feed conveyor extending across the direction of movement of the tumbling conveyor and through the tumbling zone, both said conveyors contacting the Workpieces so as to feed the Workpieces -through the mill as they are being tumbled, said mill having a feed station at one side of the tumbling zone for feeding the Workpieces into contact With the feed conveyor and a discharge station at the other side of the tumbling zone for receiving workpieces from the feed conveyor.

DAVID C. TURNBULL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 10 Number Name Date 1,729,671 Bell-Irving et al. Oct. 1, 1929 2,047,106 Lidberg et al July 7, 1936 2,131,772 Turnbull Oct. 4, 1938 2,204,588 Guite June 18, 1940 15 2,447,802 Hirsch Aug. 24, 1948 FOREIGN PATENTS Number Country Date 20,637 Great Britain Sept. 17, 1906 

